Dryer control system



Oct. 12, 1965 D. G. LYCAN 3,21

DRYER CONTROL SYSTEM Filed June 27, 1962 1" i 15 I HI 2 Sheets-Sheet l INVENTOR. J y/v40 4 A70? 4 T WWI Oct. 12, 1965 Filed June 27, 1962 r r 3 g 2'70 zw 5060 I Log 40 30 //6 20 D. G. LYCAN DRYER CONTROL SYSTEM 2 Sheets-Sheet 2 INVENTOR. fla/wuo 4. LX640 Irv-Tammy United States Patent 3,210,862 DRYER CONTROL SYSTEM Donald G. Lycan, Birmingham, Mich., assignor to American Motors Corporation, Detroit, Mich., a corporation of Maryland Filed June 27, 1962, Ser. No. 205,629 14 Claims. (Cl. 3445) This invention relates to laundry appliances for the drying of clothes, fabrics, and the like and more particularly to electrical control systems used in such appliances.

It is an object of the present invention to provide in a clothes dryer an improved control system whereby the dryer may be selectively operated to produce a plurality of different clothes treating operations, with a suitable type of control being available for each operation.

Another object of the present invention is to provide an improved control system for clothes dryers so they may be selectitvely operated to produce a plurality of different operations; a clothes drying operation of timed length with thermostatically controlled heat, a clothes tumbling operation of timed length without heat, and a clothes drying operation whose length is automatically varied to produce the correct drying period for fully drying the clothes with selectable thermostatically controlled heat to correspond to the clothes being dried.

A further object of the present invention is to provide an improved control arrangement for a clothes dryer including dual temperature responsive controls wherein each through the manual setting of the control knob may be selectively placed in control of the heating element.

A further object of the present invention is to provide an improved control arrangement for a clothes dryer including dual temperature responsive controls wherein each may be selectively placed in control of the dryer heating element and wherein one of the temperature responsive controls initiates and cycles the operation of the timing controls to provide for an automatically determined drying period. for the fully drying of the clothes.

A further object of the present invention is to provide an improved signal arrangement for a clothes dryer wherein upon completion of the drying operation with the stoppage of the clothes tumbling and air circulation an audible signal is given and continues until the timer terminates itself.

A further object of the present invention is to provide a signal arrangement for a clothes dryer in a new and novel arrangement.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the invention is clearly shown.

FIG. 1 is a vertical view in cross section of a clothes dryer embodying features of my invention,

FIG. 2 is a fragmentary view taken along line 22 of FIG. 1,

FIG. 3 is a schematic diagram of a control sytem embodying my invention, and

FIG. 4 is a chart showing the sequence of operation of the timer operated switches included in the system of FIG. 3.

Shown in the drawings is a clothes dryer comprising in general a casing 12 within which is a drum or tumbler 14 rotatably mounted upon a plurality of rollers 16 which are grouped and arranged to provide a cradle support and a drive for the drum 14. The rollers 16 are mounted on shafts 18, 20 respectively for rotation therewith The shafts 18, 20 are extended between spaced parallel upright walls 22, 24 and are journaled thereto. The shaft 18 is operatively connected to be driven by an 3,210,862 Patented Oct. 12, 1965 ice electric motor 26 through a belt drive 28. The motor 26 is supported upon a base 30 of the cabinet. The uprights 22, 24 are secured to the base 30 to extend upwardly therefrom in a spaced relation to a respective end of the drum 14.

The drum 14 comprises a cylindrical wall 32 and end walls 34, 36. The end walls are each formed with a central opening 38, 40 respectively. The opening 38 is closed by a stationary closure plate 42 secured to the upright wall 22. The peripheral edge of the plate 42 overlies the end wall 34 and carries a sealing member 44 which is adapted to extend to and frictionally engage the end wall 34. The sealing member 44 extends circumferentially about the opening 35. An opening 46 is formed in the closure plate 42 which forms an outlet for a passage 48 formed in a vertically extended duct 50. The lower end of the duct is open for entrance of air to flow upwardly therethrough and into the drum. Positioned within the passage 48 is an electrical heating element 52.

Fixed to the upright 24 is an annular ring 56 held in spatial relation to the end wall 36 of the drum. Sealing members 58, 60 extend concentrically about the opening 40. Each of the sealing members 58, 60 are secured to the annular ring 56 to extend across for frictional engagement with the end wall 36 of the drum. Protruding through the annular ring 56 and through the opening 40, is a neck or collar 62. The collar 62 extends rearwardly from the front wall 66 of the casing 10 .and into the opening 40 to serve as an access opening into the drum, and which opening is closed by a suitable door 68. The door 68 is preferably hinged (not shown) to the front wall 66.

A vertically extended duct 70, forming a passage 72, is positioned between the upright wall 24 and the front wall 66. The upper end of the duct is turned to extend laterally adjacent the collar 62 and is provided with an inlet opening 74 through which the interior of the drum is in open communication with the passage 72. The lower end of the duct is turned to extend laterally, as at 76, to extend the pasage 72 into an inlet of an air moving device or blower 78. A duct connects to extend the outlet of the blower 78 exterior to the casing 10. The blower 78 is operatively connected to be driven by the motor 26.

Suitable openings 82 are provided in the front wall 66 for entry of air to circulate into the casing 10 and from where it is withdrawn to pass upwardly through the duct 50 wherein it is heated by contact with the heating element 52. From the duct 50 the heated air passes into the rotating drum to circulate through the clothes tumbling therein to effect their drying. The moisture laden air is withdrawn from the drum to pass through the opening 74 into the passage 72. A screen filter 84 is positioned within the passage 72 to trap and remove lint and other foreign matter before the air passes into the blower 78. The blower forces the air to pass outwardly through the conduit 80 to the atmosphere. If desired the conduit 80 may be extended by duct extensions (not shown) whereby the dscharge may be at some point remote from the dryer.

The operation of my heating element 52 and the motor 26 is controlled by my new and improved control sys tern which is schematically shown in FIGS. 3 and 4. The control system 100 includes in general a timer 102, a pair of cycling thermostats including switches 104, 106 respectively, and a safety thermostat including a switch 108. v

The cycling thermostats with their switches 104, 106 are preferably secured on the plate 42 to extend into the drum 14 for sensing the air temperature therein. However, they may be positioned in any other suitable location relative to the drum providing that they sense to respond to the air temperature within the drum. To deenergize the heating element 52 the switch 104 is actuated when the air temperature has attained preferably 150 F., and the switch 106 is actuated when the air temperature has attained preferably 170 F. The safety thermostat with switch 108 is shown located in the air duct 50 between the heating element 52 and the inlet to the drum 14. The switch 108 is actuated should the selected cycling thermostatically operated switches 104 or 106 fail to function and the air temperature attains or rises above 108 F. Should this occur the safety thermostatically operated switch 108 will deenergize the heating element 52 thereby preventing overheating or burning of the clothes within the drum. This will be more fully set out.

The timer 102 is preferably mounted within a housing 110 on the casing 12. The timer 102 comprises a pair of cams 112, 114 which are mounted upon a common shaft 116 for rotation therewith. The shaft 116 is pro vided with a control knob and pointer 118 for a manual rotation for the presetting of the cams. The knob and pointer 118 may be rotated in either a clockwise or counter-clockwise direction to manually preset the cams. The shaft 116 is operatively connected to be driven in a counter-clockwise direction by a timer motor 120. The cam 112 directly engages a switch blade or reed having a contact 130. The periphery of the cam 112 is so arranged (not shown) that at various rotated positions it is adapted to move the contact 130 against a contact 132, or it may engage together contacts 130, 132 and 134, or it may move together contacts 130, 132, 134 and 136.

Each of the contacts 132, 134, 136 may be suitably mounted on a respective flexible reed, switch blade or the like to effect movement relative to each other. Preferably the reeds are arranged to flex and carry their respective contact out of engagement from the adjacent contact as the cam releases its pressure on the reeds.

The cam 114 directly engages a flexible reed or switch blade having a contact 140. The cam 114 is so arranged (not shown) that by its rotation it effects a movement of the contact 140 to move towards and upon an adjacent contact 142, and a further rotation to effect a movement of the engaged contacts 140, 142 upon a contact 144. The contacts 142, 144, like contact 140, are mounted on a respective flexible reed. The reeds are adapted to carry their respective contacts out ofengagement with the adjacent contact as the cam releases its pressure thereupon.

Connected to a suitable source of power supply are conductors 150, 152 and 154. A circuit across the conductor 150 with either conductor 152 or 154 provides current preferably of 115 volts. The circuit across the conductors 152, 154 provides current of higher voltage, preferably of 230 volts.

The contacts 140 and 130 are suitably connected in parallel to the conductor 152. The conductor 150 connects to a door switch 156 of a single throw double pole type. A pole 158 of the switch 156 is connected to a drum light 160 which connects to the conductor 154.

The other pole 162 of the switch 156 is connected by a conductor 164 to the energizing windings 166 of the drive motor 26. The windings 166 are connected by a conductor 168 to the contact 132.

Provided within the drive motor 26 are two switches 170, 172. Each of the switches 170, 172 are of well known types, and each being actuated by centrifugal force effected by the rotation of the drive motor 26. The switch 170 is arranged to being moved and held in a closed position during the operation, or running, of the drive motor, while the switch 172 is arranged to being moved and held in open position during the operation of the drive motor. The switch 172 is normally closed with the motor stopped and is connected by a conductor 164 to the pole 162 of the door switch 156, and by a conductor 174 to an electro-magnetic type buzzer or signalling device 176. Though an audible signalling device is preferably shown, a signal light or similar device may, if

desired, be substituted. The signalling device 176 is in turn connected by a conductor 178 to a terminal 180.

Connected to the terminal 180 are the conductors 182, 184, 186. The terminal 180 being connected by the conductor 182 to the timer contact 142, by the conductor 184 to contacts 188, 190 of the thermostatically operated switches 104, 108, respectively, in series circuit, and by the conductor 186 to the timer motor 120. The timer motor being connected by a conductor 192 to the pole 162 of the door switch 156.

The thermostatically operated switches 104, 108 are similar in construction. The switch 104 comprises a switch arm 200 normally in engagement with a contact 202. The switch 108 comprises a switch arm 204 normally in engagement with a contact 206. Each of the switch arms 200, 204 being operatively connected to respective thermostats (not shown) for being biased thereby in response to the air temperature Within the drum. When the air temperature reaches a predetermined value, as preferably F. the arm 200 is biased to engage upon the contact 188, whereas the arm 204 is biased upon the contact 190 when the air temperature attains a predetermined higher value, as preferably 180 F. As the air cools and the temperature falls the switch arms 200, 204 will, at respective predetermined temperatures, each be biased to reclose upon their respective contacts 202, 206.

The thermostatically operated switch 106 comprises a switch arm 208 adapted to being biased to make or break with a contact 210. The switch arm 208 being operatively connected to a thermostat (not shown) and is actuated to disengage from the contact 210 when the air temperature attains a predetermined value, as preferably F., and reengage the contact 210 when the air temperature falls to a predetermined low value.

The timer contact 134 is connected by a conductor 220 to the switch arm 200 of the switch 104. The switch arm 200 also being connected by a conductor 222 through a manually operated switch 224 to the timer contact 144.

The timer contact 136 is connected by a conductor 226 to the switch arm 208 of the switch 106. The contact 210 is connected in series with the contact 202 of the switch 104, and to the switch arm 204 of the switch 106 by a conductor 228. The contact 206 is connected by a conductor 230 to the heating element 52 which in turn is connected by a conductor 232 to the centrifugally operated switch 170 within the drive motor 26. The switch 170 being connected to the power supply conductor 154.

Associated with the control knob 118 of the timer 102 is a stationary dial 236. The face of the dial is marked, or divided into zones or arcuate sections 240, 250, 260. Rotating the knob and pointer 118 so that it stops within either the arcuate section 240, or 250, sets the control system to provide a temperature modified clothes drying operation which automatically determines the drying period to fully dry the clothes. Setting the pointer within the section 240 is preferably for the drying of clothes or fabrics which are generally known as wash-wear, that is, the fabrics are of synethtic material having the characteristics of absorbing little or no moisture, and to dry requires chiefly the evaporation of the surface moisture therefrom as opposed to fabrics of organic material, such as cotton or wool, which absorb moisture. For the drying of the latter fabrics the pointer is set within the section 250 which is provided with markings 252, 254 that permits the user to vary the automatically determined drying period to correspond to the moisture absorbing qualities of the articles composing the load. Setting the pointer for a starting position on the mark 252 provides automatically a drying period for a load composed of heavy moisture absorbing articles such as hand rugs, bedspreads and the like. For normal fabrics the drying of the latter fabrics the pointer is set within the pointer opposite the marking 254 and a starting setting intermediate the marking 254 and the off position mark;

ing 256 provides automatically a drying period for thin or delicate fabrics.

The sections 240, 250 further permit the user to adjust the control system to a setting to provide for the individuals own degree of dryness requirement. That is, each individual has a personal requirement as to the degree of dryness that is suitable for folding and storing,

or a dryness suitable for ironing or the like. In each requirement some percentage of natural moisture retention is desired in the clothes as opposed to a so-called bone dry condition which is found to be undesirable as the fabric is then without its natural moisture and this makes the fabric feel harsh to the touch, and brittle. Further it is also necessary to adjust the control system for garments that have heavy seams, lapped or folded over sewed sections that dry slower. The control system can be varied to provide the degree of dryness required by adjusting the starting setting through the positioning of the pointer. If the starting setting is varied towards either extreme in the respective section selected, that is 240 or 250, a corresponding change is had in the degree of dryness. The percentage of natural moisture retained in the garments will proportionately increase as the starting setting is advanced towards the off position of the respectively selected section, and is proportionately decreased when the starting setting is advanced towards the opposite extreme furthest from the off position.

A setting of the pointer within the zone or arcuate section 260 on the dial preselects a timed drying operation of predetermined length as is noted by the marking on the dial to which the pointer 118 is preset.

Rotating and setting the pointer into any section on the dial 236 rotates and positions the cams 112, 114 to preset respective contacts which are graphically shown in FIG. 4. The period of inter-engagement of the contacts for and during the selected Operation of the control system are shown by cross hatching and will be more fully explained hereinafter.

Manually setting the pointer into any portion within the section 250 on the dial correspondingly rotates and positions the cams 112, 114 so as to preset respective contacts and circuits as follows. The cam 112 being preset to effect to move together in inter-engagement the contacts 130, 132, 134. This energizes the drive motor and the heating element.

The drive motor 26 is energized through a circuit as follows: conductor 150, closed door switch 156 to pole 162, conductor 164 to the drive motor windings 166, conductor 168, closed contacts 130, 132 and conductor 152. With the operation of the drive motor the switch 170 is closed to energize the preset circuit to the heating element as follows; conductor 152, closed contacts 130, 132, 134, conductor 220 to the cycling thermostatically operated switch 104 through the switch arm 200 and contact 202, conductor 228 to the safety thermostatically operated switch 204 and contact 206, conductor 230, heating element 52, conductor 232, closed switch 170 and conductor 154. The following automatic drying action is initiated.

The heated air enters the rotating drum to circulate about and through the tumbling wet clothes. The moisture laden air is Withdrawn from the drum by the blower to be passed to the atmosphere. A portion of the heated air circulated about the tumbling clothes is applied to raise the temperature of the clothes and a portion will tend to vaporize the moisture present on and in the clothes. The effect of the latent heat to vaporize the moisture acts to reduce the temperature of the clothes. Eventually a balanced condition is reached between the increase in sensible heat and the cooling effect of vaporization to temporarily stop the rise in air temperature within the drum so that for a period thereafter the clothes will continue to dry at a constant temperature. The length of this period and the temperature value at which the drying for this period occurs will vary for different loads being dependent upon the quantity of articles, the heat input, the air flow and the wetness of the articles. As the drying period continues the surface moisture is reduced which in turn reduces the cooling effect due to vaporization. This results in a new rapid increase in the temperature of the clothes with a resultant increase in the exhaust air until it reaches a temperature value to effect actuation of the switch 104. The switch arm 200 is then thermostatically biased to disengage from the contact 262 and to engage upon the contact 188. This movement of the switch deenergizes the heating element 52 and energizes the timer motor through a circuit as follows: conductor 152, closed contacts 130, 132, 134, conductor 220, switch arm 200 upon contact 188 in switch 104, conductors 184, 136, timer motor 120, conductor 192, the closed door switch 156 and conductor 150.

The energized timer motor will operate to rotate the cams in a counter-clockwise direction until the air temperature falls below a predetermined value whereupon the switch 104 will be thermostatically actuated to bias the switch arm 200 to reclose upon the contact 202. The timer motor is deenergized and the heating element is reenergized alternately thereafter in response to the air temperature. The drive motor 26 continues uninterruptingly during the cycling. This cycling will continue until the timer motor has advanced the timers cams to initiate a cool down period and thereafter terminate the drying cycle.

In the progressive drying of the clothes each heater on will be shorter in duration, and each successive heater off will be longer in duration as the clothes become dryer. This results in a drying cycle that is partially self-compensating for the variations in the moisture content of each load. By manually setting the pointer in a proper portion in the section or zone 250 on the dial, in accordance to the load or type of load placed in the dryer, the timer cams are preset to automatically provide for the necessary longer or shorter period of drying time necessary for the natural moisture retention desired in the garments by the user.

The cycling air heating period terminates when the cam 112 has been rotated to effect a separation of the contact 134 from the contact 132. The contact 132 remains in engagement with the contact to continue energizing the motor 26 for a predetermined longer period after the heating element is de-energized. Just prior to the disengagement of the contact 134 the cam 114 has been rotated to effect the closing of the contact upon the contact 142 to energize the timer motor 120 through a circuit as follows: conductor 152, closed contacts 140, 142, conductors 182, 186, timer motor 120, conductor 192, closed door switch 156 and conductor 150. The timer motor 120 will operate to provide a predetermined cool down period during which time the clothes are tumbled and cooled by circulating unheated air there through. At the end of this period the cam 112 will eifect a separation of the contacts 130, 132 which opens the circuit to deenergize and stop the drive motor 26. Upon the stoppage of the drive motor the internal switch 172, kept open by centrifugal force, will close to energize the audible signal device 176 through a circuit as follows; conductor 150, closed door switch 156, conductor 164, closed switch 172, conductor 174, audible signal device 176, conductors 17$, 182, closed contacts 142, 140 and conductor 152. The energized signal device 176 will sound an audible alarm during this concluding period of operation. The signal device 176 and the timer motor 120 are simultaneously energized until the timer motor has rotated the cam 114 to effect a separation of the contacts 140, 142 which deenergizes simultaneously the timer motor and the signal device .to end the drying operation. At the conclusion of the drying operation the pointer 118 will have been rotated and stopped by the timer motor at the denoted off marking 256 on the dial.

Setting the pointer 118 at any point within the zone or section 240 on the dial provides an automatically modified clothes drying operation similar to that described above, except that the heating element 52 is under the control of the thermostatically operated switch 106, and as this drying operation is preferably for garments of the washer-wear type, it is desirable that the heating element be energized to provide high heat for rapid drying with the recycling periods held to a minimum.

The pointer 118 being set within the section 240 presets the cam 112 to effect a biasing to move together in interengagement the contacts 130, 132, 134 and 136. This closes circuits energizing the drive motor 26 and the heating element 52. The circuit energizing the drive motor is the same as that previously described through the closure of contacts 130, 132. The heating element is energized under control of the thermostatically operated switch 106 through a circuit as follows; conductor 152, closed contacts 130, 132, 134, 136, conductor 226, the closed thermostatically operated switch 106, conductor 228, switch arm 204 upon contact 206 of the switch 108, conductor 230, heating element 52, conductor 232, closed switch 170 and conductor 154.

It will be noted that from the contact 134 through the thermostatically operated switch 104 there is a parallel circuit to the heating element. As the switch 104 is influenced to be actuated at a lower temperature value, preferably 150 F., then the switch 106, preferably 170 F., the heating element will be cycled under control of the switch 106. As the temperature attains the first value to influence the thermostatically operated switch 104, the switch arm 200 is biased to disengage from the contact 202 .to engage upon the timer contact 188 to close a circuit energizing the timer motor 120. The timer motor begins operating prior to the ending of the first heating cycle under control of the thermostatically operated switch 106. The circuit from the contact 188 being through conductors 184, 186, timer motor 120, conductor 192, closed door switch 156 and the conductor 150.

The first heating cycle here is the same as described above wherein drying continues at a constant temperature until there is a reduction in the moisture content to reduce or minimize the cooling effect of vaporization and thereafter allowing an increase in sensible heat. With the heating element under control of the switch 106 the air temperature will rise to a higher value than under control of the switch 104 before the heating element is deenergized. As this drying operation is preferably adapted for garments and fabrics of the wash-wear type, the moisture being mostly on the surface of the fabric, it is desirable that the fabrics be dried in relatively high heat. Once the air temperature reaches the predetermined high value the surface moisture is generally evaporated and the fabrics are considered fully dried. For this reason it is preferable that there be a single energizing period for the heating element. However, should there be a rapid cool down the switch 106 may reenergize the heating element prior to the timer motor actuating the cams to initiate a cool down operational period.

The timer motor 120 once energized by the switch 104 remains energized irrespective whether the switch 106 reenergizes the heating element beyond the first heating period. The thermostat operating the switch 106 cycles the heating element to maintain temperature values that satisfy the thermostatically operate-d switch 104 so that it cannot be actuated to disengage from the timer contact 188. That is, the switch 104 is actuated upon a cooling to preferably, 150 F. to reenergize the heating element, whereas a cooling to, preferably, 130 F. is required before the switch 104 will be actuated to deenergize the timer motor. The cams are arranged for rotation by the timer motor for a predetermined period sufficient to at least allow the first heating period to be terminated by the switch 106 whereupon the cam 112 effects a simultaneous separation of the contact 136 from contact 134 and contact 134 from contact 132 which opens all circuits to the heating element. Prior to this action by the cam 112, the cam 114 had effected the closing of the contact 140 upon the contact 142 to provide a circuit to continue the operation of the timer motor before the circuit through the contact 134 is broken. For a predetermined period the clothes will be tumbled in the rotating drum with unheated air circulated threthrough to cool the clothes. At the conclusion of this cool down period the cam 112 has been rotated to effect a separation of the contact 132 from contact to open the circuit stopping the drive motor 26. The stoppage of the motor 26 closes the switch 172 to energize the signal device 176 to sound an audible alarm. The circuit to the signal device is through the closed contacts 140, 142 and it will remain energized with the timer motor for a predetermined period until the cam 114 has been rotated to effect a separation of the contacts 140, 142. This terminates the preselected drying operation with the pointer 118 having been rotated and stopped opposite the off marking 244 on the dial.

In the manufacture of the timer it is generally made with a slight play or relative movement allowance between the cams and the shaft. This play allowance becomes a disadvantage when the manual presetting of the cams is by counter clockwise rotation for a presetting in section 240, or 250, and particularly if it is made at the marginal starting point for the longest, or fullest drying period. Making such a marginal setting there often occurs, upon the manual release of the pointer 118 by the user, a backlash of the cams which results in a failure to properly actuate the necessary contacts into proper engagement and results in initiating only a partial operation, or none at all. To insure the proper start from the extreme starting position the cam 114 is arranged to effect a closing of the contact upon the contact 142 (see FIG. 4). This connects from contact 142 and through conductors 182, 186 the timer motor 120 in a circuit as already described above. The timer motor will remain energized for a predetermined period sufficient to rotate and advance the cams to effect the proper presetting, that is the closing of the necessary contacts for the preselected drying and thereafter the cam 114 advances to effect a separation of the contacts 140, 142.

Rotatably setting the pointer 118 within the zone or section 260 on the dial initiates a straight time controlled operation for either heated air drying or unheated air tumbling operation. The length or duration of the period being that as selected by the user in setting the pointer to a designated time marking on the dial. The timer motor will be energized from the initial start to the terminated end of the period. The thermostatically operated switch 104 cycles the heating element when heated air circulation is desired. If unheated air is desired the manually operated switch 224 is manually actuated to open position.

With the pointer set in any part of the section 260 the earn 114 is preset to effect a closing together in interengagement for the contacts 140, 142 and 144. Also the cam 112 is preset to effect the interen-gagement of the contacts 130, 132. The closed contacts 130, 132 close a circuit, previously described above, to energize the drive motor 26. The timer motor is energized by the closed contacts 140, 142 through a circuit previously described above. The heating element 52 is energized under control of the thermostatically operated switch 104 through a circuit as follows: conductor 152, closed contacts 140, 142, 144, conductor 222, closed switch 224, switch arm 200 upon contact 202, conductor 228, the switch arm 204 upon contact 206 of the switch 108, conductor 230, heating element 52, conductor 232, closed switch and conductor 154.

At a predetermined interval before the termination of operation, the timer motors rotation of the cam 114 will effect a separation of contact 144 from cont-act 142 to deenergize and terminate operation of the heating element.

. 9 The timer motor and drive motor continue its operation to provide a cooling period whereby the clothes are tumbled in unheated circulating air. After a further period the cam 112 will have been advanced to effect a separation of the contacts 130, 132 to terminate the operation of the drive motor 26. With the drive motor stopped the switch 172 closes to energize the signal device 176 to provide an audible alarm. Shortly thereafter the cam 112 has been advanced to etfect separation of the contacts 140, 142 to open the circuits to the signal device and the timer motor to conclude and terminate the timed drying operation.

To provide for a timed fiuffing operation, that is, tumbling the clothes with unheated air circulating through the rotating drum for a predetermined period. The pointer 118 is preset to a desired marking within the arcuate section 260 on the dial, and the switch 224 is manually actuated to open position. The circuits and operation are the same as described above for straight time drying except that the heating element circuit preset by the timer cannot energize the heating element as the switch 224 is in open position. The drive motor is sequentially stopped before the timer motor and the signal device will be energized to provide an audible signal for the interim period in the same manner as pre viously described.

The door operated switch 156 is mounted to the cabinet (not shown) in a manner whereby an opening of the door moves the switch arm to engage upon the contact 158 to energize the drum light 160. With the breaking oil? with the contact 162, because the door is open, no drying operation may be initiated until the door is reclosed. If the door is opened during the operation of the dryer then the operation will be halted and resumed at the point of stoppage upon the reclosing of the door.

If the heating element was energized it Would be deenergized through the stoppage of the drive motor 26 by the opening of the switch 170. If the timer motor was in operation for automatic drying, as described above, and the door was opened and held open for a period sufficient to lower the temperature sufliciently so that the controlling thermostatically operated switch is actuated to call for heating of the air the timer motor will not be reenergized upon the reclosing of the door until the circulating air has again attained the required temperatures.

From the above it will be noted that there is provided a control system for a clothes dryer permitting the user a choice of methods for drying, for fully drying automatically or automatically drying to a degree of dryness as desired, as well as a choice for automatically drying in accordance to the type fabrics. The user may preselect and adjust the control system as to the quantity, type and kind of fabrics that are to be dried. Further, the control system includes an arrangement to insure the starting and the operation of the automatic drying operation at all initial setting points. Also, there is provided an audible signal or alarm that the drying period is terminating.

Although only a preferred form of the invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A control system for a clothes dryer having a rotating drum, a drive motor for rotating said drum, power supply, a control circuit, a normally closed switch centrifugally operated to open position by said drive motor, a timer having sequentially operated switch means; said drive motor, said switch and said timer sequentially operated switch means being interconnected in said control circuit, an electrically energizable signalling means being connected in said control circuit in series with said centrifugally operated switch, and said sequentially oper- 1% ated switch means being arranged in said control circuit to first disconnect from said power supply said drive motor and after a predetermined longer period said centrifugally operated switch.

2. A control system for a clothes dryer having a rotary drum, prime moving means for rotating said drum, power supply, timer, a timer motor operably connected for driving said timer, control circuit means for interconnecting said timer said timer motor, and said prime moving means to said power supply, said timer motor being operative of said timer for disconnecting said prime moving means from said power supply prior to disconnecting said timer motor therefrom, switch means in normally closed position, means for actuating and holding said switch means in open position during operation of said prime moving means, an electrically energizable signalling means, said switch means and said signalling means being connected in series and in said control circuit in parallel with said timer motor.

3. A control system for a clothes dryer having a rotating drum, prime moving means for rotating said drum, heating element, power supply, a switch normally in closed position, means for actuating and holding said switch in open position during the operation of said prime moving means, an electrically energizable signalling means, timer means, a control circuit connecting said power supply to each of said heating element and said prime moving means and to said switch in series with said timer means, said timer means being arranged in said control circuit to disconnect said power supply sequentially, first from said heating element, after a predetermined longer period from said prime moving means and thereafter upon a predetermined longer period from said switch, and said signalling means being connected in said control circuit means in series connection with said switch.

4. A control system for a clothes dryer having a rotating drum, a drive motor for rotating said drum, a heating element, timer, a timer motor for operably driving said timer, power supply, control circuit means, a plurality of thermostatically operated switches being connected in circuits for controlling the energization and deenergization of said heating element, said thermostatically operated switches being each responsive for being actuated each in a difierent range of temperature values, at least one of said thermostatically operated switches having a contact being connected in circuit with said heating element and a contact being connected in circuit with said timer motor for alternately energizing first said heating element and deenergizing said timer motor and thereafter deenergizing said heating element and energizing said timer motor, said timer having selectively operated means for connecting in circuits with said power supply said drive motor said timer motor and said heating element, means for adjusting said timer to selectively place said timer motor and heating element under the energization control of at least one of said thermostatically operated switches, said drive motor having a normally closed switch centrifugally operated to open position, an electrically energizable signalling means, and said normally closed switch and signalling means being connected together in series circuit and in parallel with said timer motor for energizing said signalling means when said motor is deenergized and prior to the de-energization of said timer motor.

5. A control system for a clothes dryer having a rotating drum, prime moving means for rotating said drum, a heating element, a switch normally in closed position, means for actuating and holding said switch in open position during the operation of said prime moving means, a timer, a timer motor being operably connected to drive said timer, power supply, circuit means, an electrically energized signal means, thermostatically operated switch means having a heater contact and a timer contact, said heater contact being connected in circuit to said heating element, said timer contact being connected in circuit to said timer motor, said timer having sequentially operated switch means being operable to selectively connect in circuit relation said power supply to said prime moving means and said thermostatically operated switch means, said thermostatically operated switch means in response to predetermined low temperatures being actuated to energize said heating element and in response to predetermined high temperatures to energize said timer motor, said timer motor driving said timer to operate said sequentially operated switch means to first connect said power supply to said normally closed switch and to said timer motor, thereafter disconnecting said heating element, said prime moving means and at an interval thereafter said switch, and said signal device being connected in circuit with said switch in series connection.

6. A control system for a clothes dryer having a drive motor, heating element, timer, timer motor for operably driving said timer, power supply, control circuit means a plurality of thermostatically operated switches being each responsive for actuation in a different range of temperature values, each of said thermostatically operated switches having a heater contact being connected in circuit with said heating element and at least one of said thermostatically operated switches having a heater contact being connected in circuit with said heating element and a timer contact being connected in circuit with said timer motor, said timer having a plurality of sequentially operated switch means; said timer motor, said drive motor and each of said thermostatically operated switch being each connected in circuit with a respective switch means, said power supply being connected in circuit with said switch means, said timer including means operative in one position thereof for actuating said sequential switch means to energize said drive motor, and said heating element and said drive motor together, and whereby said heating element and said drive motor are alternately energized by said thermostatically operated switch having a heater and a timer contact, and said timer having means operative in another position thereof to actuate respective switch means to energize said drive motor, and said heating element and said drive motor, whereby said heating element is energized under control of one thermostatically operated switch and said timer motor under the control of another thermostatically operated switch having a timer contact, and manually operated means to adjust said timer into one of said operative positions.

7. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the circulating air, a control system comprising a timer, a timer motor for driving said timer, a first thermostatically operated switch having a heater contact and a timer contact, a second thermostatically operated switch having a heater contact, circuit means, said timer having sequentially actuated switch means including a first, second, third and fourth switch means, said second switch means being connected in circuit with said first thermostatically operated switch, said third switch means being connected in circuit with said second thermostatically operated switch, said heater contacts of said first and of said second thermostatically operated switches being connected in circuit to said heating element in parallel circuits, said timer contact of said first thermo statically operated switch being connected in circuit with said timer motor, a switch operable by said drive motor to open position and returned to closed position upon the stopping of said drive motor, an electrically operated signal means being connected in parallel circuit with said timer motor, said fourth switch means and said last mentioned switch being in series circuit, means for manually adjusting said timer to selectively actuate said second switch means to closed position for initiating the energization of said heating element and thereafter said timer motor and said heater alternately by said first thermostatically operated switch, said means also manually adjusting said timer to selectively actuate said second and third switch means to closed position for energizing said heating element and thereafter said first thermostatically operated switch energizing said heater and timer motor at a predetermined higher temperature, and said timer being operably driven by said timer motor for a predetermined period for actuating said fourth switch to closed position and thereafter at intervals the opening of said second, third and first switch means, the sequential opening of said first switch means de-energizing said drive motor and energizing said signal means, and shortly thereafter said signal means and said timer motor being deenergized by the opening of said fourth switch means.

8. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a timer motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature, and a timed clothes drying operation; a plurality of thermostatically operated switches comprising a first and a second switch each being operated thermostatically and each being actuated at different predetermined high and low air temperatures, said first thermostatically operated switch having 'heater contacts and timer contacts and being adapted to alternately open said heater and close said timer contact upon a predetermined high air temperature and opening said timer contacts and reclosing said heater contacts at a predetermined low temperature, said second thermostatically operated switch having a heater contact and being actuated to open at predetermined high air temperatures and to close at predetermined low air temperatures, said control system including a plurality of timer operated switching means and circuit means, said timer having different presettable operating ranges and operating said switching means in at least one .of said ranges to initially energize said heating element under control 'of said first or second thermostatically operated switches, and thereafter, with the selection of said first thermostatically operated switch alternately energizing said timer motor and said heating element, and with the selection of said second thermostatically operated switch said timer motor being energized by said first thermostatically operated switch upon a closing of its timer contact, and in still another of said presettable operating range said timer operating said switching means to energize said heating element under control of one of said thermostatically operated switches and simultaneously energizing said timer motor independently of said thermostatically operated switch, in said last mentioned preselectable operating range a manually operated switch connected in series circuit with said heating element wherein said heating element is deenergized upon the manual opening of said switch, one of said timer operated switching means operable in each of the different presettable operating ranges to energize said drive motor, and means for manually adjusting said timer to adjust said control system in one of said presettable operating ranges to produce the desired one of said operations.

9. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a timer motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature and a timed clothes drying operation; a first and a second thermostatically operated switch, the first of said thermostatically operated switches having a heater contact and a timer contact, said first switch being actuated in response to predetermined high temperatures to open said heater contact and close said timer contact and in response to predetermined low temperature to reclose said heater contact and open said timer contact, said second thermostatically operated switch having a heater contact, said second switch being actuated in response to predetermined high temperatures to open said heater contact and reclose said contact at predetermined low temperatures, said second switch being actuated in response to predetermined higher air temperatures than said first switch for the opening and closing of their respective heater contacts, said control system including switch means comprising. a first group of first, second, third and fourth contacts, and a second group of fifth and sixth contacts; a first circuit for energizing said drive motor upon closing said first upon said second cont acts, a second circuit energizing said heating element being connected with said first thermostatically operated switch and the interengagement of said first, second and third contacts, a third circuit energizing said heating element being connected with said second thermostatically operated switch and the interengagement of the contacts in said first group, a fourth circuit energizing said timer motor being connected upon the interengagement of the contacts in said second group, a circuit interconnecting said timer contact of said first thermostatically operated switch and said timer motor, said timer having difierent presettable operating ranges and operating said contacts to produce selectively a first temperature modified clothes drying operation to provide said first and second circuits, a second temperature modified clothes drying operation to provide said first and third circuits, a timed drying operation to provide said first, second and fourth circuits, said presettable operating ranges of said timer being arranged to operatively control said second and said third circuits wherein the selection of said second circuit being provided with a longer period of energization of the heating element then the selection of the other circuit, means for manually adjusting said timer to adjust said control system to produce the desired one of said operations.

10. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating throughsaid tumbling means, a control system including a timer and a timer motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature and a timed clothes drying operation; a first and a second thermostatically operated switch, the first of said thermostatically operated switches having a heater contact and a timer contact, said first switch being actuated in response to predetermined high temperatures to open said heater contact and close said timer contact and in response to predetermined low temperatures to reclose said heater contact and open said timer contact, said second thermostatically operated switch having a heater contact, said second thermostatically operated switch being actuated in response to predetermined high temperatures to open said heater contact and reclose said contact at predetermined low temperatures, said second thermostatically operated switch being actuated in response to predetermined higher air temperatures than said first thermostatically operated switch for the opening and closing of their respective heater contacts, said control system including switch means comprising a first group, first, second, third and fourth contacts, and a second group of fifth, sixth and seventh contact-s, a switch manually operable between open and closed positions, a first circuit for energizing said drive motor upon closing said first upon said second contacts, a second circuit energizing said heating element being connected with said heater contact of said first thermostatically operated switch and the interengagement of said first, second and third contacts, a third circuit energizing said heating element being connected with said second thermostatically operated switch and the interengagement of said first group of contacts, a fourth circuit energizing said heating element being connected with said 'heater contact of said first thermostatically operated switch and the interengagement of said first group of contacts, a fifth circuit energizing said timer motor upon closing said fifth upon said sixth contact, a circuit interconnecting said timer contact and said timer motor, said timer motor having different presettable opera-ting ranges and operating said first through seventh contacts to produce selectively a first temperature modified clothes drying operation to provide said first and second circuits, a second temperature modified clothes drying operation to provide first, second and third circuits, a timed drying operation or a timed tumbling operation without heat to provide said first, second, and fifth circuits wherein said manually op erable switch is preset in closed position tor a timed drying operation and preset in open position for timed tumbling operation, said presettable operating ranges of said timer being arranged to operatively control said second circuit for a longer period for energization of said heating element than said third circuit, and manual means for adjusting said timer to adjust said control system to produce the desired one of said operations.

11. A control system for a clothes dryer having a drive motor, heating element, timer, timer motor for operably driving said timer, a first and a second thermostatically operated switch, control circuit means, power supply for energizing said control circuit means, said first thermostatically operated switch having a heater contact being connected in circuit with said heating element and a timer contact being connected in circuit with said timer motor, said second thermostatically operated switch having a heater contact being connected in circuit with said heating element, said timer having a plurality of sequentially operated switch means, said first and said second thermostatically operated switch, said drive motor and said timer motor being each connected in circuit with a respective switch means of said timer, means for adjusting to condition said timer in a first or a second position to energize said drive motor and said heating element, in said first position said heating element and said timer motor being energized under control of said first thermostatically operated switch, in said second position said heating element being energized under control of said second thermostatically operated switch and said timer motor being energized under control of said first thermostatically operated switch, said first thermostatically operated switch being actuated in response to low temperatures to close said heater contact to energize said heating element and be disengaged from said timer contact to deenergize said timer motor and in response to high temperatures to disengage from said heater contact deenergizing said heating element and engaging said timer contact to energize said timer motor, said second thermostatically operated switch being actuated to close said heater contact in response to low temperature values and open said contact in response to temperature values higher than said first thermostatically operated switch responds to deenergize said heating element, said second thermostatically operated switch arranged further to energize said heating element to main temperatures at values to maintain said first thermostatically operated switch closed upon said timer contact to energize said timer motor, and said timer having means being driven by said timer motor to actuate respective switch means to deenergize said drive motor and heating element after a predetermined period of energization of said timer motor for said second adjusted position and for a predetermined longer period of energization of said timer motor for said first adjusted position.

12. A control system for a clothes dryer having a drive motor, heating element, timer, timer motor for operably driving said timer, a first and a second thermostatically operated switch, control circuit means, power supply for energizing said control circuit means, said first thermostatically operated switch having a heater contact being connected in circuit with said heating element and a timer contact being connected in circuit with said timer motor, said second thermostatically operated switch having a heater contact being connected in circuit with said heating element, and timer having a plurality of sequentially operated switch means, said first and said second thermostatically operated switch, said drive motor and said time motor being each connected in circuit with a re spective switch means of said timer, means for adjusting to condition said timer in a first or a second position to energize said drive motor and said heating element, in said first position said heating element and said timer motor being energized under control of said first thermostatically operated switch, in said second position said heating element being energized under control of said second thermostatically operated switch and said timer motor being energized under control of said first thermostatically operated switch, said first thermostatically operated switch being actuated in response to low temperatures to close said heater contact to energize said heating element and be disengaged from said timer contact to deenergize said timer motor contact deenergizing said heating element and engaging said timer contact to energize said timer motor, said second thermostatically operated switch being actuated to close said heater contact in response to low temperature values and open said contact in response to temperature values higher than said first thermostatically operated switch responds to deenergize said heating element, said second thermostatically operated switch arranged further to energize said heating element to maintain temperatures at values to maintain said first thermostatically operated switch closed upon said timer contact to energize said timer motor, an electrically energizable signalling means, said drive motor having a normally closed switch centrifugally operated to open position, said signalling means, said normally closed switch being connected in circuit with a respective switch means of said timer in series connection, said timer having means being driven by said timer motor to actuate respective switch means to first deenergize said heating element after a predetermined period of energization of said timer motor for said second adjusted position and for a predetermined longer period of energization of said timer motor for said first adjusted position,

16 said thereafter actuating switch means to deenergize said drive motor and an interval thereafter said switch means to deenergize said signalling means energized upon the deenergization of said drive motor.

13. In a signal-control system for clothes dryers including a drive motor, a timer, timer operated control switches, drive motor responsive centrifugal switches, signal means, and a source of electrical power, the improvement, comprising; said drive motor and one of said timer operated control switches being connected in series with said source of power, said timer and another of said timer operated control switches being connected in series with each other and to said power source in parallel with said drive motor and the control switch which is in series connection therewith, and said signal means and a centrifugal switch which is closed when said drive motor is inactive being connected to said power source in parallel with said timer, said timer being operative first of the control switch in series conection with said drive motor for disconnecting said motor from said power source and closing the centrifugal switch to activate said signal means and after a predetermined period of time for disconnecting the control switch connecting itself and said signal means to said power source.

14. In a control system for clothes dryers including a drive motor, a heater, a timer, a source of electrical power and timer controlled switches connecting said drive motor and heater to said source of electrical power, the improvement, comprising; temperature responsive switches for intermittently disconnecting said heater from said source of power and connecting said timer thereto, said temperature responsive switches including a pair thereof connected in series and responsive to respectively different temperature conditions and a third connected in parallel with one of said pair for obtaining a still higher safe-guarded temperature condition, and a timer controlled switch for holding said timer in energized engagement with said source of power after a period of intermittent operation under the control of said temperature responsive switches.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM F. ODEA, Acting Primary Examiner. NORMAN YUDKOFF. Examiner. 

1. A CONTROL SYSTEM FOR A CLOTHES DRYER HAVING A ROTATING DRUM, A DRIVE MOTOR FORO ROTATING SAID DRUM, POWER SUPPLY, A CONTROL CIRCUIT, A NORMALLY CLOSED SWITCH CENTRIFUGALLY OPERATED TO OPEN POSITION BY SAID DRIVE MOTOR, A TIMER HAVING SEQUENTIALLY OPERATED SWITCH MEANS; SAID DRIVE MOTOR, SAID SWITCH AND SAID TIMER SEQUENTIALLY OPERATED SWITCH MEANS BEING INTERCONNECTED IN SAID CONTROL CIRCUIT, AN ELECTRICALLY ENERGIZABLE SIGNALLING MEANS BEING CONNECTED IN SAID CONTROL CIRCUIT IN SERIES WITH SAID CENTRIFUGALLY OPERATED SWITCH, AND SAID SEQUENTIALLY OPERATED SWITCH MEANS BEING ARRANGED IN SAID CONTROL CIRCUIT TO FIRST DISCONNECT FROM SAID POWER SUPPLY SAID DRIVE MOTOR AND AFTER A PREDETERMINED LONGER PERIOD SAID CENTRIFUGALLY OPERATED SWITCH. 